ISOM 350

Business Application Development

Mohammad AlMarzouq

HTML Forms

What Are Forms?

• HTML component
• Used to send user input to server
• POST forms include data in the body
• GET forms include data in the url
• Submit button is needed to perform submit action

Post Form

<form action="" method="POST">
  <!-- data input components here -->
  <input type=submit>
</form>

GET Form

<form action="" method="GET">
  <!-- data input components here -->
  <input type=submit>
</form>

Data Input Components

• These are the components used to get input from the user
• There are numerous types depending on type of input you need from the user
• Input types include
  • text, checkbox, radio, email, password …etc
  • We typically use label tag to add labels
  • List can be found here

Form Example

Create the following GET form in a Django template:

<form action="" method="GET">

  <label for="username">Username:</label>
  <input type="text" name="username">
  <br />
  <label for="pwd">Password:</label>
  <input type="password" name="pwd">

  <input type=submit>
</form>

Form Input

• Open the view with the form then enter some data
• Click the submit button and see what happens
• Notice the importance of the name property in the input tag
  • It specifies the variable name that holds the data

Using Form Input in Views

• Depending on form type (GET vs POST) you access request.GET or request.POST
• Both are just python dictionaries
• Use the name value as the key to fetch the data in the input

Using Form Input in Views

def form_view(request):
  print("Username:", request.GET.get("username"))
  print("Password:", request.GET.get("pwd"))
  return render(request, "form.html")

• Use the values from the dictionary as you would any variable

GET Vs POST Form

• Replace the form method to POST
• Submit some data
  • Can you spot the difference?
  • Fix the view so the data would be printed correctly

GET Vs POST Form

• Do you think POST is more secure than GET?
• You answer should be no! both are insecure
• You need to use https and Django Forms to improve security
• Using POST is preferable in that case
• GET is more convenient when security is not a concern
  • Search and simple data input

Exercise

Create a calculator view where the user:

• Inputs two values
• Chooses the operation
• Gets the result when the form is submitted

Final Thoughts

• Using forms the way we did is not secure
• You can use it for search queries and simple input
• Django Forms is used to make forms more secure
  • Covered in future topic